Methods and devices are known, with which it is possible to store speech information where the stored speech information is provided with digital identification signal words in order to facilitate the retrieval of certain speech information for reproduction or for transmission purposes.
In the patent specification DE 33 33 958 A1 a device is described for the storage of speech information which contains a controllable generator through which digital identification signal words are produced by means of a keyboard. These are recorded with or separately from the speech information and used for a later search for the retrieval of the information as required.
It is a disadvantage for the user because he has to classify the speech information in order to be able to start a search operation for certain speech information.
In the U.S. Pat. No. 5,602,963 a electronic personal organiser is described which is capable of recording and reproducing voice messages. The organiser also has a function which allows the user, following the recording of a voice message, to be able to mark this by means of an input of one or several spoken words for retrieval at a later date.
This approach has the disadvantage in that for each voice message, provided a classification is desired, the classification must be explicitly carried out by the user after the recording of the message. The amount of words, which can be searched for, must be specified beforehand. These words must be pre-spoken beforehand in a training phase. The processing of the speech signals in the organiser is effected by means of various processing functions, depending on whether the speech is to be recorded or compared with a pre-specified vocabulary.
In the U.S. Pat. No. 4,829,576, and for the purpose of increasing the probability for the correct recognition of a word, it is proposed that only those words are to be adopted for comparison from the specified vocabulary which are contained in the text part to be searched. For this purpose, a SEARCH WORD LIST is formed in a separate step.
In the U.S. Pat. No. 6,041,300 a method and a device are described, according to which and for the purpose of improving the speech selection, the speech is to be transformed in a sequence of lefemes, which is compared with the previously stored lefeme-sequences. The recognised word, for conformation by the user, is synthesised from the stored sequence of lefemes in the database and issued.
A disadvantage here, in particular, is the fact that the establishment of a database is necessary as a first step.